this does get tricky. then there is quoting and not quoting, symbols or
lists, and even another angle I saw just now in the up command where
it talks of "previously saved values" for a sym.

I think it gets worse before it gets better, but I'm making progress. ;)

That rot or xchg are destructive is fine, also the difference between
that and non-destructive. But I am wondering about how the set and nth
work together to force an operation to be destructive, like here:

: (set 'A '(a b c))
-> (a b c)
: (set 'B A)       
-> (a b c)
: (set (nth A 1) 'x)       
-> x
: A                 
-> (x b c)
: B
-> (x b c)

while a set alone is not destructive, B points at the original value:

: (set 'A '(a b c d))
-> (a b c d)
: B                  
-> (x b c)

an eval of A and (nth A 1) both yield (a b c), so why is one
destructive and the other is not? that little single quote?

so on a hunch tried this, and it worked:

: (set (val 'A) 'x)

but what did I just do???
-- 
UNSUBSCRIBE: mailto:[email protected]?subject=Unsubscribe

Reply via email to